Hydro-pneumatic feed mechanism for a tool carrier



L. E. KRAFFT Jan. 9, 1968v HYDRO-PNEUMATIC FEED MECHANISM FOR A TOOL CARRIER Filed Oct. 15, 1965 5 Sheets-Sheet 1 ATTORNEY" Jan. 9, 1968 L. E. KRAFFT 3,352,256

I HYDROPNEUMATIC FEED MECHANISM FOR A TOOL CARRIER Filed Oct. 15, 1965 5 Sheets-Sheet 5 :20 63 60 FIG. 5 2

(NC) L7 I090. W (UP) L 63 W (DOWN) i R [I22 /"L6 INVENTOR. L c LevxnsY-IKroffl WSW ATTORNEY United States Patent r 3,362,266 HYDRO-PNEUMATIC FEED MECHANISM FOR A TOOL CARRIER Lewis E. Kraflt't, 245 S. Park, Bensenville, Ill. 60106 Filed Oct. 15, 1965, Ser. No. 496,584 16 Claims. (Cl. 77-335) This invention relates to machine tools such as drills or boring mills and more specifically to a novel hydropneumatic operating mechanism therefor.

In tools which are relatively advanced and retracted with respect to a work piece it is particularly important to control the advance of the tool toward the work piece at a slow rate especially when working on so called exotic metals which are especially hard and brittle. It is also imperative that the speed and the length of stroke of the tool can be varied with ease and to operate automatically. Further, for flexibility, it is necessary that the mechanism be adjustable for rapid advance, if desired.

A general object of the invention is to provide a novel device which obtains a compact and eflicient unit wherein the mechanism for operating the tool carrier incorporates a closed hydraulic circuit wherein the fluid is controllably metered during advance of the tool and rapidly shuttled to retract the carrier.

A further object of the invention is to provide a novel device for operating the tool carrier in which mechanism is afforded which may be easily adjusted to control the advance and return of the tool carrier.

The invention comprehends a system wherein the tool carrier comprises a piston operative within a cylinder subdividing it into axially spaced advance and retract chambers, the retract cylinder thus opposing the advance cylinder and the former containing hydraulic fluid which is metered into a reservoir under the action of air under pressure being selectively injected into the advance chamber, the rate of advance being governed by the rate of flow of the fluid from the retract cylinder.

More specifically, the invention contemplates the provision of a novel throttle valve arrangement comprising a stem adjustably connected to the tool carrier and its position with respect to the carrier being determinative of the nature of the movement of the carrier by controlling the flow characteristics of the fluid.

A specific object of the invention is to provide a novel mechanism for operating the tool carrier which comprises a piston formed on a quill intermediate the ends thereof, the quill being of cylindrical cross section and having end portions projecting from opposite ends of a cylinder in fluid sealed engagement therewith, the piston forming advance and retract chambers with opposite ends of the cylinder and the quill mounting a power unit at one end comprising preferably an electric motor, the motor driving a shaft which is journaled through the quill which, at its other end, mounts a tool chuck for a drill or the like, the quill being actuated axially by a pneumatic system sequentially injecting and exhausting air into and out of the advance chamber while the retract chamber is alternately filled with fluid and exhausted of fluid, the exhausting or discharge of fluid from the retract chamber being controlled by a manually settable needle valve and by an auxiliary throttle valve forming a stem movable with the tool carrier whereby the position and thereby the action of the throttle valve is the function of the position of the tool carrier.

The invention also comprehends the provision of a novel switching arrangement including an actuator carried from the tool carrier, the actuator being adjustable to control the stroke of the carrier.

These and other objects and advantages inherent in and encompassing the invention will become more readily apparent from the specifications and the drawings wherein:

FIGURE 1 is a side elevational view partly in section of the novel tool mechanism incorporating the invention;

FIGURE 2 is a fragmentary view comparable to FIG- URE 1 showing the parts in advanced position;

FIGURE 3 is a horizontal or transaxial sectional view taken substantially on line 3-3 of FIGURE 1;

FIGURE 4 is a sectional view taken substantially on line 44 of FIGURE 3;

FIGURE 5 is a further fragmentary side elevational view partly in section taken substantially on line 5-5 of FIGURE 3; and

FIGURE 6 is a schematic View of the electric circuitry.

Describing the invention in detail and having particular reference to the drawing the machine tool generally designated 2 comprises a support frame 3 which for the purposes of illustration only may be integrated with the work table 5 which carries the work piece 6 to be operated upon by a tool such as the drill 7 as shown.

The drill 7 is carried removably in a chuck 8 which may be rotatably supported in a holder 9 threaded into the lower tubular end portion 10 of the quill 11 of a tool holder generally designated 12. The quill may be a hollow structure and have an axial bore 13 which admits a drive shaft 14 therethrough. The shaft 14 extends through the upper end portion 15 of the quill and is suitably connected to an electric or pneumatic motor 16 which may have an air filter screen 18 mounted about its air impeller (not shown) of conventional form which is used to cool the motor when operating under heavy loads. The housing 19 which mounts the screen is provided with securing lugs 20 which extend axially along the upper portion 15 of the quill and are secured by boss sleeve 22 extending through axially aligned apertures 23 in the portion 15 and lugs 20. The sleeves 22 provide a passage for the electrical cord 25 (or air hose if a pneumatic motor is used) which is connected to the motor 16 and to a source of power.

The quill 11 is embraced by a stop collar 28 which is split at 29 and embraces the upper portion 15 of the quill and is thereby adjustably axially thereon. The portions of the split ring are clamped about the portion 15 and held in adjusted position by a screw 30 securing the portions of the ring tightly about the quill. The collar 28 is guided axially by a shouldered screw 32 which has a head 33 at its upper end limiting upward movement of the collar and thus the quill. The screw extends axially of the quill at one side thereof through an opening 34 in the collar and at its lower end is threaded into the body block 35 which incorporates a cylinder structure 36 and a reservoir structure 37.

The cylinder structure 36 is formed at one end of the block 35 and admits a piston portion 38 formed integral with the quill 11 intermediate its ends for reciprocation within the bore 39 of the cylinder portion 36. The cylinder 36 is provided at opposite ends with upper and lower bearing caps 40 and 41 which closely embrace the upper and lower portions 15 and 10 of the quill 11. The caps 40, 41 are secured as by bolts 42, 43 to the upper and lower ends 44, 45 of the cylinder. The bearing caps 40 and 41 are each provided with suitable sealing rings 47, 48 which seal against the peripheries 49, 50 of the upper and lower portions 15, 11 of the quill, respectively.

The piston 38 has upper and lower grooved lands 52, 53 with sealing rings 52 53 therein sealing against the surface of the bore 39 and between the lands 52, 53 the piston is provided with an axially wide groove 54 within which there is carried a felt material wiper and sealing ring 54 The piston 38 subdivides the cylinder into upper and lower or advance and retract chambers 55, 56.

The upper quill chamber communicates with a combination pressure and exhaust or vent port 58 which is connected to a passageway 59 through which air under pressure is admitted through a valve 60 which is interposed in the passage or line 59 between the port 58 and a pressure line 70 delivering a constant source of air under pressure. Upon the advance stroke or movement of the tool, the valve 60 is opened to unseat the stem 61 from the seat 62 by energizing the solenoid 63 as hereinafter explained. The air is ported through the passage 59 via the chamber 64 in the valve to the advance chamber 55. At the same time fluid 68 is being exhausted from the retract chamber 56. The rate of flow of the fluid 68 is controlled to determine the rate of movement of the tool as hereinafter explained. The fluid flows through a combination inlet outlet port 70a through a passage 71 and communicates with a vertical bore or chamber 72 which has a constricted lower portion 73 closely approximating the diameter of the throttle stem 75 which as shown in FIGURE 4 has its lower end 76 within the radially enlarged upper portion 77 of the bore 72 with the tool carrier shown in its ultimate retracted position. The stem 75 is guided in a sleeve 78 which is provided with internal and external grooves 79, 80 carrying 0 rings 81 and 82 therein and respectively sealingly engaging the bore surface of upper portion 77 of bore 72 and the periphery of the stem 75. The stem 75 reciprocates axially or vertically in bore 72. In the position of FIGURE 4 the fluid can flow unrestrictively upwardly in bore portion 73 and out through passage 72a into the fluid chamber 83 below the free or floating piston 84 which has sealing engagement at 86, 87 with the surface of the reservoir cylinder 88. The piston is downwardly actuated by a spring 89 which reacts at its lower end against the seating surface 90 of the piston and has its lower end encased within the upwardly open bore 91 in the piston and the upper end of the spring reacts against the upper side 92 of the air or gas chamber 93. As the quill descends or advances, and depending upon the axial position of the adjusting screw 94 with its nut lock 94a secured to the collar 28, the screw 94 abutting against the upper or outer end of the stem 75, said stem 75 will eventually have its lower end 76, which is tapered at 96 to pilot the stem into portion 73 of bore 72, entered into portion 73 at which time the rate of advance of the quill will appreciably slow down. This may be set to correspond with the time that the tool engages the work. Thereafter all of the fluid must flow through the metered line 97 at the lower end of portion 73 of bore 72, it being understood that some fluid flowed through 97 upon flow through passage 72a. Fluid flowing through passage 97 which is continued in end cap 98, closing the lower end of cylinder 88, and secured to block 35 by cap screws 99, and into a metering valve bore 100 which has a narrowed outlet port 101 communicating with chamber 83. The bore 100 has a needle or metering valve 102 therein which has a grooved land 103 provided with a sealing ring 104 in sealed engagement with the surface of bore 100. Stem 102 is adjustable axially by the adjusting bolt 105 which is secured and locked to the cap 98 by the locking nut and sleeve structure 107. Adjustment of stem projects or withdraws its narrow upper end portion 108 with respect to port 101 thus governing the flow rate of the fluid from chamber 56 to chamber 83. Thus the advance speed of the quill and the tool carried thereby can be very accurately controlled,

To retract the tool, the air is evacuated from the gas chamber 55 by deenergizing valve 60 whereupon the spring therein opens the valve permitting the air to exhaust to the atmosphere, the air escaping from passage 59 and at the same time the spring urges the stem 61 to close the line to the air supply. The air exhausts through chamber 64 via pasage 64a in stem 61 past the open port 62a and passage 63a. Simultaneously the up air valve 109 is energized by solenoid 109a acting against spring 10% shifting its stem 109a to unseat from the valve seat 109d in the pressure inlet line 110 whereupon pressured air is ported through chamber 112 and into the passage 113 into the gas chamber 93 urging the piston 84 downwardly.

The valve 109 is similarly provided like valve 60 with air exhaust passage 110a, exhaust port 110b, and exhaust passage 1100 to atmosphere to exhaust air from passage 112 upon de-energizing of solenoid 109a. The increased pressure in chamber 83 unseats the one way check or ball valve 114 allowing rapid flow of fluid past the ball while compressing spring 116, the fluid passing through passage 97 into bore 73 and passage 71 and port 70a into chamber 56. As the quill rises, it being understood that air has been exhausted from chamber 55, the throttle valve stem 75 withdraws from portion 73 of bore 72 whereupon fluid flows from chamber 83 into passage 72a to bore 72.

The collar 28 carries an adjustable abutment screw threaded through the collar and locked by locking nut 121, the screw contacting a microswitch 122 through spring loaded plunger 124b to stop the descent of the tool and to de-energize the down or advance air valve 60. A switch stern 124 is adjustably secured to collar 28 by lock nut 124a and has cam lobe 125 which has its cam surfaces 126 and 127 contacted by switch 128 carried by block 35 to condition the electric circuit E for operation of the solenoids 63 and 109a. The microswitch 128 is the normally closed type, i.e., if uninfluenced by the cam 125 the switch 128 is closed and its part of circuit E is closed and current may flow therethrough. The microswitch button 129 of switch 128 is moved inwardly by cam surfaces 126 and 127 (in the up position of drill 7) and opens switch 128 and its part of circuit E but as soon ast the drill 7 moves down and button rides on cam surface 126, the spring loaded button 129 is allowed to move out and place the switch 128 in the normal closed circuit position allowing current to go through its part of the circuit E. Of cource the stopping and starting of the unit may be manually controlled if desired and for certain operations this may be preferable. An operation of the valves 60 and 109 is explained by reference to the electric circuit E as shown schematically by FIGURE 6 as follows:

The electric circuit E has the usual two leads or lines L and L connected to a source of power (not shown) for completing the electric circuit. Line L has branch lines L and L and line L has branch lines L and L L is provided with a relay R having a relay solenoid R operating relay switch R to carry its relay electrical conducting arms R and R together in unison from contacts C and C to contacts C and C; respectively when relay solenoid R is energized. Line L electrically connects with arm R and line L; connects with arm R Line L connects with relay R and has start button or S.B., line L has switch 122 and contact C line L, has solenoid (up) 109a and contact C and line L; has solenoid (down) 63 and contact C Contact C is electrically insulated or out of the circuit.

FIGURE 6 shows schematically the circuit for operation of the machine 2 whereby the selector switch R is set to automatic position and the start or on button (which is normally open) S.B. is depressed and the relay R is energized moving electrical contacts C and C down (from solid line position 1 to the dotted position 2) to complete the circuit through the solenoid valve 60 energizing same and valve 60 moves up to open pressure line 70 to line 59 which results in lowering of the drill 7. When element 120 contacts microswitch 122 which is normally closed and is a momentary switch, the switch 122 opens momentarily opening the circuit of the relay and contacts C and C move back to position 1 and since start button S.B. is open, the circuit to solenoid valve 60 is open deenergizing solenoid valve 60 and circuit to solenoid valve 109 is closed energizing solenoid valve 109 to let line 70 communicate with line 110 and chambers 93 to raise drill 7. At the top of the stroke of drill 7 switch 128 which normally closed is opened momentarily, opening or de-energizing the circuit for starting the next cycle. Switch 128 is held open by surface 127 of the cam 125 conditioning the circuit for the next cycle but when the on button SE. is depressed to initiate the next cycle, the movement downward of the drill 7 carries the cam member 125 down with cam surface 126 passing over switch 127 allowing switch button 128 to move out allowing closing of switch 128.

The cylinder 36 has an air vent or groove 39a between the bore 39 and the outside for allowing any entrapped air between groove 54 and the 'bore 36 that has seeped from chamber 55 to escape to the atmosphere. Therefore, the air under pressure in chamber 55 going past sealing ring 52 can not go past sealing ring 53 into the hydraulic fluid. If air were allowed to pass into the hydraulic fluid chamber 56 the hydraulic fluid would become frothy and drop off in pressure and this in turn would cause the movement or functioning of the drill to be improper or erratic. The vent 39a prevents this from happening. The width of the groove 54 is greater than the stroke distance of the piston so that the groove 39a is always between the seals 52 and 53 Similarly, a groove or air vent 91a in the reservoir structure 37 communicates bore 88 with the atmosphere, the vent opening 91a always being between seals with the travel of the piston 84 always keeping the vent 91a between the seals 86 and 87. Therefore air or gas under pressure in chamber 93 that passes through seal 86 is vented to the atmosphere and does not pass through seal 87 into the hydraulic fluid in chamber 83 to lower the operating pressures and cause malfunctioning of the tool.

The foregoing description and drawings are given merely to explain and illustrate my invention and the invention is not limited thereto, except insofar as the appended claims are so limited, since those skilled in the art who have my disclosure before them will be able to make modifications and variationstherein without departing from the scope of the invention.

I claim:

1. A machine tool carrier for advancing and retracting a tool toward and away from a work piece comprising a tool support, a tool quill reciprocably mounted in said support, said tool support comprising a cylinder and said tool quill comprising a piston means reciprocably disposed in fluid sealing engagement with said cylinder, said piston means forming advance and retract chambers with opposite ends of the cylinder, said quill mounting a power unit for rotating the drill, the power unit having a shaft driven thereby and carrying a tool chuck, pneumatic transmitting means communicating with the advance chamber and sequentially injecting and exhausting gas into and out of the advance chamber, said retract chamber having means for supplying and exhausting hydraulic fluid therefrom including a fluid reservoir means comprising a cylinder having a floating piston to define a pair of chamber sections, one chamber section having sequential communication with the pneumatic transmitting means and the other chamber section having communication with the retract chamber, flow control means including manually settable needle valve means disposed between the retract chamber and the other chamber section in restricting flow of hydraulic fluid from the retract chamber to the other chamber section, check valve means directing flow from the other chamber section to the retract chamber, and throttle valve means mounted for movement with said quill and reciprocable in flow obstructing relation between the retract chamber and the other chamber section whereby the position and thereby the action of the throttle valve means is the function of the position of the tool quill, and said carrier having means operating said pneumatic transmitting means for sequentially injecting and exhausting gas into and out of the advance chamber and the one chamber section while the retract chamber and the other chamber section are alternately filled and exhausted of hydraulic fluid.

2. A machine tool carrier for advancing and retracting a. tool toward and away from a work piece comprising a cylinder, a tool chuck carrying means comprising a first piston reciprocably disposed in the cylinder and forming at opposite ends thereof a gas receiving advance chamber and a hydraulic fluid receiving retract chamber, a second cylinder and piston defining a reservoir means for hydraulic fluid and communicating with the retract chamber and a second gas chamber, pneumatic transmitting means selectively and alternately communicating with each gas chamber for movement of said pistons, and hydraulic fluid control means in flow obstructing position between the retract chamber and the reservoir means comprising first and second passage means communicating between the reservoir means and the retract chamber, check valve means in the first passage means allowing fluid flo-w only to the retract chamber and flow restricting valve means in the first passage, throttle valve means constrained for movement with the tool chuck carrying means in a tool advancing direction and reciprocably disposed in fluid blocking position in said second passage means in the advanced position of the throttle valve means to provide for two-speed advancing movement of the quill.

3. A machine tool carrier for advancing and retracting a tool toward and away from a work piece comprising a tool support, a tool quill reciprocably mounted in said support, said tool support comprising a cylinder and said tool quill comprising a piston means reciprocably disposed in fluid sealing engagement with said cylinder, said piston means forming advance and retract chambers with opposite ends of the cylinder, said quill mounting a power unit for rotating the drill, the power unit having a shaft driven thereby and carrying a tool chuck, pneumatic transmitting means communicating with the advance chamber and sequentially injecting and exhausting gas into and out of the advance chamber, said retract chamber having means for supplying and exhausting hydraulic fluid there from including a fluid reservoir means comprising a cylinder having a floating piston to define a pair of chamber sections, one chamber section having sequential communication with the pneumatic transmitting means and the other chamber section having communication with the retract chamber, flow control means including means disposed between the retract chamber and the other chamber section in restricting flow of hydraulic fluid from the retract chamber to the other chamber section, one way flow means directing flow from the other chamber section to the retract chamber, and throttle means mounted for movement with said quill and reciprocable in flow obstructing relation between the retract chamber and the other chamber section whereby the position and thereby the action of the throttle valve means is the function of the position of the tool quill, and said carrier having means operating said pneumatic transmitting means for sequentially injecting and exhausting gas into and out of the advance chamber and the one chamber section while the retract chamber and the other chamber section are alternately filled and exhausted of hydraulic fluid.

4. A machine tool carrier for advancing and retracting a tool toward and away from a work piece comprising a cylinder, a tool chuck carrying means comprising a first piston reciprocably disposed in the cylinder and forming at opposite ends thereof a gas receiving advance chamber and a hydraulic fluid receiving retract chamber, a second cylinder and piston defining a reservoir means for hydraulic fluid and communicating with the retract chamber and a second gas chamber, pneumatic transmitting means selectively and alternately communicating with each gas chamber for movement of said pistons, and hydraulic fluid control means in flow obstructing position between the retract chamber and the reservoir means comprising check valve means allowing fluid flow only to the retract cham ber and flow restricting valve means, and throttle valve means constrained for movement with the tool chuck carrying means in a tool advancing direction and reciprocably disposed in fluid blocking position in the advanced position of the throttle valve means to provide for twospeed advancing movement of the quill.

5. A machine tool carrier for advancing and retracting a tool toward and away from a work piece comprising a cylinder, a tool chuck carrying means comprising a first piston reciprocably disposed in the cylinder and forming at opposite ends thereof a gas receiving advance chamber and a hydraulic fluid receiving retract chamber, a second cylinder and piston defining a reservoir means for hydraulic fluid and communicating with the retract chamber and a second gas chamber, pneumatic transmitting means selectively and alternately communicating with each gas chamber for movement of said pistons, and hydraulic fluid control means in flow obstructing position between the retract chamber and the reservoir means comprising check valve means allowing fluid flow only to the retract chamber and flow restricting valve means, and throttle valve means constrained for movement with the tool chuck carrying means in a tool advancing direction and reciprocably disposed in fluid blocking position in the advanced position of the throttle valve means to provide for two-speed advancing movement of the quill, and said carrier having means operating said pneumatic transmitting means for sequentially injecting and exhausting gas out of the gas chambers while the retract chamber and reservoir means are alternately filled and exhausted of hydraulic fluid.

6. A machine tool carrier for advancing and retracting a tool toward and away from a work piece comprising a tool support, a tool quill reciprocably mounted in said support, said tool support comprising a cylinder and said tool quill comprising a piston means reciprocably disposed in fluid sealing engagement with said cylinder, said piston means forming advance and retract chambers with opposite ends of the cylinder, said quill mounting a power unit for rotating the drill, the power unit having a shaft driven thereby and carrying a tool chuck, pneumatic transmitting means communicating with the advance chamber and sequentially injecting and exhausting gas into and out of the advance chamber, said retract chamber having means for supplying and exhausting hydraulic fluid therefrom including a fluid reservoir means comprising a cylinder having a floating piston to define a pair of chamber sections, one chamber section having sequential communication with the pneumatic transmitting means and the other chamber section having communication with the retract chamber, flow control means including means disposed between the retract chamber and the other chamber section in restricting flow of hydraulic fluid from the retract chamber to the other chamber section, one way flow means directing flow from the other chamber section to the retract chamber, and throttle means mounted for movement with said quill and reciprocable in flow obstructing relation between the retract chamber and the other chamber section whereby the position and thereby the action of the throttle valve means is the function of the position of the tool quill, and said carrier having means operating said pneumatic transmitting means for sequentially injecting and exhausting gas into and out of the advance chamber and the one chamber section while the retract chamber and the other chamber section are alternately filled and exhausted of hydraulic fluid, said piston means and said floating piston each being provided with a pair of spaced sealing means for separation of gas from hydraulic fluid and each cylinder being provided with vent means communicating with the interior of a respective cylinder between the respective pair of sealing means and with the outside of a respective cylinder.

7. A machine tool carrier for advancing and retracting a tool toward and away from a work piece comprising a tool support, a tool quill reciprocably mounted in said support, said tool support comprising a cylinder and said tool quill comprising a piston means reciprocably disposed in fluid sealing engagement with said cylinder, said piston means forming advance and retract chambers with opposite ends of the cylinder, said quill mounting a power unit for rotating the drill, the power unit having a shaft driven thereby and carrying a tool chuck, pneumatic transmitting means communicating with the advance chamber and sequentially injecting and exhausting gas into and out of the advance chamber, said retract chamber having means for supplying and exhausting hydraulic fluid therefrom including a fluid reservoir means comprising a cylinder having a floating piston to define a pair of chamber sections, one chamber section having sequential communication with the pneumatic transmitting means and the other chamber section having communication with the retract chamber, flow control means including means disposed between the retract chamber and the other chamber section in restricting flow of hydraulic fluid from the retract chamber to the other chamber section, one way flow means directing flow from the other chamber section to the retract chamber, and throttle means mounted for movement with said quill and reciprocable in flow obstructing relation between the retract chamber and the other chamber section whereby the position and thereby the action of the throttle valve means is the function of the position of the tool quill, and said carrier having means operating said pneumatic transmitting means for sequentially injecting and exhausting gas into and out of the advance chamber and the one chamber section while the retract chamber and the other chamber section are alternately filled and exhausted of hydraulic fluid, said piston means having a pair of spaced sealing means thereabout in sealing engagement with the retract cylinder and defining a gas space therewith, said cylinder having vent means extending therethrough and communicating with the gas space.

8. A machine tool carrier for advancing and retracting a tool toward and away from a work piece comprising a cylinder, a tool chuck carrying means comprising a first piston reciprocably disposed in the cylinder and forming at opposite ends thereof a gas receiving advance chamber and a hydraulic fluid receiving retract chamber, a second cylinder and piston defining a reservoir means for hydraulic fluid and communicating with the retract chamber and a second gas chamber, pneumatic transmitting means selectively and alternately communicating with each gas chamber for movement of said pistons, and hydraulic fluid control means in flow obstructing position between the retract chamber and the reservoir means comprising check valve means allowing fluid flow only to the retract chamber and flow restricting valve means, and throttle valve means constrained for movement with the tool chuck carrying means in a tool advancing direction and reciprocably disposed in fluid blocking position in the advanced position of the throttle valve means to provide for twospeed advancing movement of the quill, said pistons means and said floating piston each being provided with a pair of spaced sealing means for separation of gas from hydraulic fluid and each cylinder being provided with vent means communicating with the interior of a respective cylinder between the respective pair of sealing means and with the outside of a respective cylinder.

9. A machine tool carrier for advancing and retracting a tool toward and away from a Work piece comprising a cylinder, a tool chuck carrying means comprising a first piston reciprocably disposed in the cylinder and forming at opposite ends thereof a gas receiving advance chamber and a hydraulic fluid receiving retract chamber, a second cylinder and piston defining a reservoir means for hydraulic fluid and communicating with the retract chamber and a second gas chamber, pneumatic transmitting means selectively and alternately communicating with each gas chamber for movement of said pistons, and hydraulic fluid control means in flow obstructing position between the retract chamber and the reservoir means comprising check valve means allowing fluid flow only to the retract chamber and flow restricting valve means, and throttle valve means constrained for movement with the tool chuck carrying means in a tool advancing direction and reciprocably disposed in fluid blocking position in the advanced position of the throttle valve means to provide for two-speed advancing movement of the quill, said piston means having a pair of spaced sealing means thereabout in sealing engagement with the retract cylinder and defining a gas space therewith, said cylinder having vent means extending therethrough and communicating with the gas space.

10. A machine tool carrier for advancing and retracting a tool toward and away from a work piece comprising a cylinder, a tool chuck carrying means comprising a first piston reciprocably disposed in the cylinder and forming at opposite ends thereof a gas receiving advance chamber and a hydraulic fluid receiving retract chamber, a second cylinder and piston defining a reservoir means for hydraulic fluid and communicating with the retract chamber and a second gas chamber, pneumatic transmitting means selectively and alternately communicating with each gas chamber for movement of said pistons, and hydraulic fluid control means in flow obstructing position between the retract chamber and the reservoir means comprising first and second passage means communicating between the reservoir means and the retract chamber, one way flow means in the first passage means allowing fluid flow only to the retract chamber and flow restricting means in the first passage, throttle means constrained for movement with the tool chuck carrying means in a tool advancing direction and reciprocably disposed in fluid blocking position in said second passage means in the advanced position of the throttle means tov provide for two-speed advancing movement of the quill. 11. Amachine tool carrier for advancing and retracting a tool toward and away from a work piece comprising a tool support, a tool quill reciprocably mounted in said support, said tool support comprising a cylinder and said tool quill comprising a piston means reciprocably disposed in fluid sealing engagement with said cylinder, said piston means forming advance and retract chambers with opposite ends of the cylinder, said quill mounting a power unit for rotating the drill, the power unit having a shaft driven thereby and carrying a tool chuck, pneumatic transmitting means communicating with the advance chamber and sequentially injecting and exhausting gas into and out of the advance chamber, said retract chamber having means for supplying and exhausting hydraulic fluid therefrom including a fluid reservoir means comprising a cylinder having a floating piston to define a pair of chamber sections, one chamber section having sequential communication with the pneumatic transmitting means and the other chamber section having communication with the retract chamber, flow control means including means disposed between the retract chamber and the other chamber section in restricting flow of hydraulic fluid from the retract chamber to the other chamber section, one way flow means directing flow from the other chamber section to the retract chamber, and throttle means mounted for movement with said quill and reciprocable in flow obstructing relation between the retract chamber and the other chamber section whereby the position and thereby the action of the throttle valve means is the function of the position of the tool quill, and said carrier having means operating said pneumatic transmitting means for sequentially injecting and exhausting gas into and out of the advance chamber and the one chamber section while the retract chamber and the other chamber section are alternately filled and exhausted of hydraulic fluid, said means operating said pneumatic transmitting means comprising a pair of electrically operated gas valves, one gas valve being energized for introduction of gas into the advance chamber and the other gas valve being de-energized for exhaust of gas from said one chamber section.

12. A machine tool carrier for advancing and retracting a tool toward and away from a work piece comprising a cylinder, a tool chuck carrying means comprising a first piston reciprocably disposed in the cylinder and forming at opposite ends thereof a gas receiving advance chamber and a hydraulic fluid receiving retract chamber, a second cylinder and piston defining a reservoir means for hydraulic fluid and communicating with the retract chamber and a second gas chamber, pneumatic transmitting means selectively and alternately communicating with each gas chamber for movement of said pistons, and hydraulic fluid control means in flow obstructing position between the retract chamber and the reservoir means comprising first and second passage means communicating between the reservoir means and the retract chamber, one way flow means in the first passage means allowing fluid flow only to the retract chamber and flow restricting means in the first passage, throttle means constrained for movement with the tool chuck carrying means in a tool advancing direction and reciprocably disposed in fluid blocking position in said second passage means in the advanced position of the throttle means to provide for two-speed advancing movement of the quill, and said carrier having means operating said pneumatic transmitting means for sequentially injecting and exhausting gas into and out of the advance chamber and the second chamber while the retract chamber and the reservoir means are alternately filled and exhausted of hydraulic fluid.

13. A machine tool carrier for advancing and retracting a tool toward and away from a work piece comprising a tool support, a tool quill reciprocably mounted in said support, said tool support comprising a cylinder and said tool quill comprising a piston means reciprocably disposed in fluid sealing engagement with said cylinder, said piston means forming advance and retract chambers with opposite ends of the cylinder, said quill mounting a power unit for rotating the drill, the power unit having a shaft driven thereby and carrying a tool chuck, pneumatic transmitting means communicating with the advance chamber and sequentially injecting and exhausting gas into and out of the advance chamber, said retract chamber having means for supplying and exhausting hydraulic fluid therefrom including a fluid reservoir means comprising a cylinder having a floating piston to define a pair of chamber sections, one chamber section having sequential communication with the pneumatic transmitting means and the other chamber section having communication with the retract chamber, flow control means including needle valve means disposed between the retract chamber and the other chamber section in restricting flow of hydraulic fluid from the retract chamber to the other chamber section, check valve means directing flow from the other chamber section to the retract chamber, and throttle valve means mounted for movement with said quill and reciprocable in flow obstructing relation between the retract chamber and the other chamber section whereby the position and thereby the action of the throttle valve means is the function of the position of the tool quill, and said carrier having means operating said pneumatic transmitting means for sequentially injecting and exhausting gas into and out of the advance chamber and the one chamber section while the retract chamber and the other chamber section are alternately filled and exhausted of hydraulic fluid.

14. A machine tool carrier for advancing and retracting a tool toward and away from a work piece comprising a tool support, a tool quill reciprocably mounted in said support, said tool support comprising a cylinder and said tool quill comprising a piston means reciprocably disposed in fluid sealing engagement with said cylinder, said piston means forming advance and retract chambers with opposite ends of the cylinder, said quill mounting a power unit for rotating the drill, the power unit having a shaft driven thereby and carrying a tool chuck, pneumatic transmitting means communicating with the advance chamber and sequentially injecting and exhausting gas into and out of the advance chamber, said retract chamber having means for supplying and exhausting hydraulic fluid therefrom including a fluid reservoir means comprising a cylinder having a floating piston to define a pair of chamber sections, one chamber section having sequential communication with the pneumatic transmitting means and the other chamber section having communication with the retract chamber, flow control means including means disposed between the retract chamber and the other chamber section in restricting flow of hydraulic fluid from the retract chamber to the other chamber section, one way flow means directing flow from the other chamber section to the retract chamber, and throttle means mounted for movement with said quill and reciprocable in flow obstructing relation between the retract chamber and the other chamber section whereby the position and thereby the action of the throttle means is the function of the position of the tool quill, and said carrier having means operating said pneumatic transmitting means for sequentially injecting and exhausting gas into and out of the advance chamber and the one chamber section while the retract chamber and the other chamber section are alternately filled and exhausted of hydraulic fluid, said means operating said pneumatic transmitting means comprising electrical means including an induction means and a starting switch operating said induction means for introducing gas into said advance chamber, and first stop means constrained for movement with said quill, and a second switch connected with said pneumatic transmitting means and engaging said first stop means in the advanced position of said quill operating said induction means for introducing gas into said one chamber and exhausting gas from said advance chamber, and second stop means constrained for movement with said quill and a third switch connected with said pneumatic transmitting means and engaging said second stop means in the retracted position of said quill for exhausting gas from said one chamber section.

15. The invention according to claim 14 and said second stop means being provided with a cam for engaging and operating said second stop means.

16. A machine tool carrier for advancing and retracting a tool toward and away from a work piece comprising a cylinder, a tool chuck carrying means comprising a first piston reciprocably disposed in the cylinder and forming at opposite ends thereof a gas receiving advance chamber and a hydraulic fluid receiving retract chamber, a second cylinder and piston defining a reservoir means for hydraulic fluid and communicating with the retract chamber and a second gas chamber, pneumatic transmitting means selectively and alternately communicating with each gas chamber for movement of said pistons, and hydraulic fluid control means in flow obstructing position between the retract chamber and the reservoir means comprising one way means allowing fluid flow only to the retract chamber and flow restricting means, and throttle means constrained for movement with the tool chuck carrying means in a tool advancing direction and reciprocably disposed in fluid blocking position in the advanced position of the throttle means to provide for two-spaced advancing movement of the quill, and said carrier having means operating said pneumatic transmitting means for sequentially injecting and exhausting gas into and out of the advance chamber and the one chamber section while the retract chamber and the other chamber section are alternately filled and exhausted of hydraulic fluid, said means operating said pneumatic transmitting means comprising electrical means including an induction means and a starting switch operating said induction means for introducing gas into said advance chamber, and first stop means constrained for movement with said quill, and a second switch connected with said pneumatic transmitting means and engaging said first stop means in the advanced position of said quill operating said induction means for introducing gas into said second gas chamber and exhausting gas from said advance chamber, and second stop means constrained with said pneumatic transmitting means and engaging said second stop means in the retraeted position of said quill for exhausting gas from said second gas chamber.

References Cited UNITED STATES PATENTS FRANCIS S. HUSAR, Primary Examiner. 

1. A MACHINE TOOL CARRIER FOR ADVANCING AND RETRACTING A TOOL TOWARD AND AWAY FROM A WORK PIECE COMPRISING A TOOL SUPPORT, A TOOL QUILL RECIPROCABLY MOUNTED IN SAID SUPPORT, SAID TOOL SUPPORT COMPRISING A CYLINDER AND SAID TOOL QUILL COMPRISING A PISTON MEANS RECIPROCABLY DISPOSED IN FLUID SEALING ENGAGEMENT WITH SAID CYLINDER, SAID PISTON MEANS FORMING ADVANCE AND RETRACT CHAMBERS WITH OPPOSITE ENDS OF THE CYLINDER, SAID QUILL MOUNTING A POWER UNIT FOR ROTATING THE DRILL, THE POWER UNIT HAVING A SHAFT DRIVEN THEREBY AND CARRYING A TOOL CHUCK, PNEUMATIC TRANSMITTING MEANS COMMUNICATING WITH THE ADVANCE CHAMBER AND SEQUENTIALLY INJECTING AN EXHAUSTING GAS INTO AND OUT OF THE ADVANCE CHAMBER, SAID RETRACR CHAMBER HAVING MEANS FOR SUPPLYING AND EXHAUSTING HYDRUALIC FLUID THEREFROM INCLUDING A FLUID RESERVOIR MEANS COMPRISING A CYLINDER HAVING A FLOATING PISTON TO DEFINE A PAIR OF CHAMBER SECTIONS, ONE CHAMBER SECTION HAVING SEQUENTIAL COMMUNICATION WITH THE PNEUMATIC TRANSMITTING MEANS AND THE OTHER CHAMBER SECTION HAVING COMMUNCATION WITH THE RETRACT CHAMBER, FLOW CONTROL MEANS INCLUDING MANUALLY SETABLE NEEDLE VALVE DISPOSED BETWEEN THE RETRACT CHAMBER AND THE OTHER CHAMBER SECTION IN RESTRICTING FLOW OF HYDRAULIC FLUID FROM THE RETRACT CHAMBER TO THE OTHER CHAMBER SECTION, CHECK VALVE MEANS DIRECTING FLOW FROM THE OTHER CHAMBER SECTION TO THE RETRACT CHAMBER, AND THROTTLE VALVE MEANS MOUNTED FOR MOVEMENT WITH SAID QUILL AND RECIPROCABLE IN FLOW OBSTRUCTING RELATION BETWEEN THE RETRACT CHAMBER AND THE OTHER CHAMBER SECTION WHEREBY THE POSITION AND THEREBY THE ACTION OF THE THROTTLE VALVE MEANS IS THE FUNCTION OF THE POSITION OF THE TOOL QUILL, AND SAID CARRIER HAVING MEANS OPERATING SAID PNEUMATIC TRANSMITTING MEANS FOR SEQUENTIALLY INJECTING AND EXHAUSTING GAS INTO AND OUT OF THE ADVANCE CHAMBER AND THE ONE CHAMBER SECTION WHILE THE RETRACT CHAMBER AND THE OTHER CHAMBER SECTION ARE ALTERNATELY FILLED AND EXHAUSTED OF HYDRAULIC FLUID. 